Primordial Germ Cells (Spermatogonial Stem Cells) of Bullfrogs Express Sex Hormone-Binding Globulin and Steroid Receptors during Seasonal Spermatogenesis

Primordial Germ Cells (Spermatogonial Stem Cells) of Bullfrogs Express Sex Hormone-Binding Globulin and Steroid Receptors during Seasonal Spermatogenesis

Author Caneguim, Breno Henrique Autor UNIFESP Google Scholar
Beltrame, Flavia Luciana Autor UNIFESP Google Scholar
Luz, Juliana Silva da Google Scholar
Valentini, Sandro Roberto Google Scholar
Cerri, Paulo Sergio Google Scholar
Sasso-Cerri, Estela Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
UNESP Univ Estadual Paulista
Abstract In vertebrate species, testosterone seems to inhibit spermatogonial differentiation and proliferation. However, this androgen can also be converted, via aromatase, into estrogen which stimulates spermatogonial differentiation and mitotic activity. During seasonal spermatogenesis of adult bullfrogs Lithobates catesbeianus, primordial germ cells (PGCs) show enhanced testosterone cytoplasm immunoexpression in winter; however, in summer, weak or no testosterone immunolabelling was observed. the aim of this study was to confirm if PGCs express stem cell markers - alkaline phosphatase (AP) activity and GFR alpha 1 (glial-cell-line-derived neurotrophic factor) - and verify whether testosterone is maintained in these cells by androgen receptors (ARs) and/or sex hormone-binding globulin (SHBG) in winter. Furthermore, regarding the possibility that testosterone is converted into estrogen by PGCs in summer, the innmunoexpression of estrogen receptor (ER)beta was investigated. Bullfrog testes were collected in winter and in summer and were embedded in glycol methacrylate for morphological analyses or in paraffin for the histochemical detection of AP activity. GFR alpha 1, AR, SHBG and ER beta expression were detected by Western blot and immunohistochemical analyses. the expression of AP activity and GFR alpha 1 in the PGCs suggest that these cells are spermatogonial stem cells. in winter, the cytoplasmic immunoexpression of ARs and SHBG in the PGCs indicates that testosterone is maintained by these proteins in these cells. the cytoplasmic immunoexpression of ER beta, in summer, also points to an ER-mediated action of estrogen in PGCs. the results indicate a participation of testosterone and estrogen in the control of the primordial spernnatogonia during the seasonal spermatogenesis of L. catesbeianus. Copyright (c) 2012 S. Karger AG, Basel
Keywords Primordial germ cells
Stem spermatogonia
Androgen and estrogen receptors
Seasonal spermatogenesis
Adult bullfrogs
Language English
Sponsor Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação para o Desenvolvimento da UNESP (FUNDUNESP)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Grant number FUNDUNESP: 00661/04-DFP
FAPESP: 2009/17895-5
Date 2013-01-01
Published in Cells Tissues Organs. Basel: Karger, v. 197, n. 2, p. 136-144, 2013.
ISSN 1422-6405 (Sherpa/Romeo, impact factor)
Publisher Karger
Extent 136-144
Access rights Closed access
Type Article
Web of Science ID WOS:000314013800005

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